Escapement lever for a timepiece



Dec. 2, 1969 P. TUETEY 3,481,140

ESCAPEMENT LEVER FOR A TIMEPIEGE Filed March 20, 1967 H62 H63 3 H51United States Patent Int. Cl. B21b13/02; B23p 13/00 US. Cl. 58116 3Claims ABSTRACT OF THE DISCLOSURE An escapement lever for a timepieceincluding pallets fitted on to the body of the lever comprising locatingsurfaces formed on a face of the lever adapted to hold the pallets intheir exact position and means for permanently affixing the pallets onthe lever.

On manufacturing escapement levers for timepieces, a single method forassembling the pallet-stones and the lever is universally used, in whichthe positioning of each pallet-stone is ensured by means of a notchforming a slide-way in which the pallet-stone is held by a resilienteffect until it is sealed by means of a thermoplastic glue, e.g.shellac. It is to be noted that in this method the pallet-stone may bedisplaced later on if the shellac is softened by heating. This is anoperation which forms a part of the escapement-making and which isintended for adjusting the functions of the escapement and forcompensating the irregularities of the manufacture of the lever as wellas those of the watch movement.

Due to the ever increasing precision of the modern manufacturingprocesses, the correction operation is more and more rare. It istherefore possible to contemplate its suppression, which enables torealize other positioning methods of the pallet-stones and to replacethe shellac by a thermosetting glue, such as Araldit (trade name), whichhas much better fixing properties and which is insensible to thecleaning products usually used by the watchmakers (especially alcoholcontaining substances) Up till now, owing to the relative strength ofthe shellac and to its sensibility to heat and certain solvents, it wasindispensable to reinforce the gluing action by a permanent means forholding the pallet-stone by the resilient effect exerted thereon by theouter lip of the notch.

The present invention aims at overcoming these drawbacks. It relates toa method of manufacturing an escapement lever for a timepiece, saidlever including pallets fitted on to the body of the lever, this methodbeing broadly characterized by forming On a face of the lever posi-,

tioning means adapted to hold the pallets in their exact position duringthe period immediately preceding their fixation on the lever, and thenfixing the pallets on the lever. In other words, the invention providespositioning means integral with or rigidly connected to the lever, bymeans of which it is possible to hold the pallets in their definitiveplace during the time necessary for the setting of the glue, inconjunction with a temporary pressure means independent of the lever andnecessitating no precise construction. The positioning means are notsufficient per se to hold the pallets in their position, as this is thecase in the well-known conventional mounting method. In addition, thepallet is glued on the plane of the lever by one of its nonfunctionalfaces (perpendicular to the lockingface), which has the advantage thatin certain cases it is possible to glue the whole surface of the palleton the lever and thus increase the strength of the assembly. This3,481,140 Patented Dec. 2, 1969 strength may be further increased byavoiding to polish the face of the pallet that is to be glued, whichincreases the adherence of the glue. In the case of metallic ormetallized pallets, the same elements as described above will facilitatethe mutual positioning of the parts during the welding operation.

The accompanying drawing shows, by way of example, an embodiment of theinvention.

FIG. 1 is a plan view of a lever equipped with its two pallet-stones.

FIG. 2 is a cross-sectional view through one of the pallet-stones fixedto the lever.

FIGS. 3 and 4 are cross-sectional views similar to FIG. 2, showingmodified embodiments.

The lever illustrated in FIGS. 1 and 2 is denoted by the referencenumeral 1 and its arbor by the reference numeral 2. The pallet-stonesare denoted by the reference numerals 3. In order to form thepositioning means for the pallet-stones 3, one resorts to the partialblanking or punching method, which consists in causing a punch topenetrate into a portion of the thickness of the lever so as to leavethe chip in its place. Thus, at least three supports or studs 4, 5 and6, for instance of a rectangular shape, are created. The surface of thelever having been preliminarily coated with glue, it is sufficient toplace the pallet-stone in its right position by pressing it against thesurface of the lever and against the studs 4 to 6, so that the correctpositioning of the pallet-stone is ensured. The studs 4 to 6 might alsobe obtained by swaging.

In a first modification, not shown, the same method as described aboveis used, but a chip having the exact shape of the pallet-stone ispartially cut out.

According to a second modification (FIG. 3), the pallet receiving placeor berth is formed by making a recess 7 in the lever 1 by means of apunch or by swaging.

In another modification (FIG. 4), a recess 8 may be obtained on thelever 1 by removal of material by a chemical or electrochemical attackor by electro-erosion, according to the known techniques used forinstance in the photo-engraving processes.

It is also possible to form permanent or temporary positioning elementsby electro-deposition or by the application of a varnish, the zoneswhich must remain free being protected during the application by masksor screens.

The use of these several methods involves that the pallet-stones 3 areno longer in the plane of the lever 1, but above this plane. The escapewheel being notably thinner than the height of the pallet-stone, itsplane will also be situated above that of the lever. Thus, it is nolonger necessary, in certain embodiments, that the functional extremityof the pallet-stone (impulse-face 9) extends beyond the outline of thelever 1 (see the dotted line in FIG. 1). This will particularlyfacilitate the use of a part of the means above described.

The positioning means above described make possible to define exactlythe position of the pallet and it is sufficient, during the period ofsetting of the glue, or during the welding operation, to exert apressure on the upper face of the pallet by simple means and withoutprecision to insure the efiiciency and the precision of the assembly.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

What I claim is:

1. In a timepiece movement,

an escapement lever having a fiat surface portion on 3 4 one sidethereof perpendicular to the axis upon References Cited which the leveriS IIlOlllltCd, the flat portion being UNITED STATES PATENTS bounded onat least three sides thereof by locating 114 372 5/1871 Wadsworth 58 116Surfaces 856,091 6/1907 Ohlson 58116 a pallet havlng a body providedwith a surface seated 5 3 248 783 5/1966 Tuetey 29 178 upon said flatsurface portion and of a shape to non- 1:327:226 1/1920 DeLongfrictionall seat within close roximit to said locatting surfa es withsaid pallef outstanid ing from said FOREIGN PATENTS one side of theescapement lever, 241,452 3/1946 Switzerland. and means for permanentlyafiixing said pallet to said 10 342,397 9 0 Sw land. escapement lever.347,140 6/ 1960 Switzerland. 2. In a timepiece movement according toclaim 1 1,163,692 9/1958 Francewherein said locating surfaces comprisestuds projecting 1,266,560 6/1961 Franceoutwardly from the plane of theescapement lever. 15 JOHN F. CAMPBELL, Primary Examiner 3. In atimepiece movement according to claim 1 wherein said fiat surfaceportion and said locating sur- REILEY Asslstant Examlner faces defineforming a recess at one face of said escape- US. Cl. X R.

ment lever. 29-177, 178; 74-15

